Hydraulic speed control system for prime movers



y 5,1942- P. A. couon 2,281,675

ayjamwmc SPEED comm. sysma FOR mm: uovnns Filed Jan. 20, 1946 4Sheets-Sheet 1 PE V 1 saws: JPEEL7LINE 5 -\Z/L D C O 1 2 3 4 5 6 7 8 IIO 11 TIME UNI T8 INVENTOR. R401. A. Como/7.

ATTORNEYS y 5, 1942' P. A. CONDIT 2,281,675

HYDRAULIC SPEED CONTROL SYSTEM FOR PRIME MOVERS Filed Jan. 20, 1940 4Sheets-Sheet 2 5b 6'7 I; E I: I 96" E 22 i0} V i 53 i E Z 07 a} 40 i I vg iii 4 I i ATTORNEYS y 1942- I P. A. CQNDIT. 2,281,675

HYDRAULIC SPEED CONTROL SYSTEM FOR PRIME MOVERS Filed Jim. 20, 1940 4Sheets-Sheet 3 \\\II IIIIIIIIIIIIIIIIIIIIIIIIIIIIIaUIIIII/I/flWl/II IINVENIOR. PA uz. A Como/7:,

BY 4,... LL4 L4 May 5, 1942. P. A. couo rr HYDRAULIC SPEED CONTROLSYSTEM FOR PRIME MOVERS Filed Jan. 20, 1940 4 Sheets-Sheet 4 Pneumo'f/cf e pressure COnfr0//en C'qmpneased '7." W4

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Compressor Cy/l'n a'er' ATTORNEYS Patented May 5, 1942 HYDRAULIC SPEEDCONTROL SYSTEM FOR PRIIVIE MOVERS Paul A. Condit, Mount Vernon, Ohio,assignor to Cooper-Bessemer Corporation, Mount Vernon, Ohio, acorporation of Ohio Application January 20, 1940, Serial No. 314,739

17 Claims.

This invention pertains to speed control systems for prime movers,particularly internal combustion engines, such as Diesel engines.

A primary object of the invention is to provide a control system whichis easily adjustable to maintain the engine speed substantiallyconstant, irrespective of load changes, at any desired speed throughoutthe full operating range of the engine, and which automatically soadjusts itself in accordance with the speed of regulation of governingspeed selected, as to eliminate hunting at all speeds.

For adjusting the governing speed from one value to another, but asingle control element is required, which may be manually adjusted atthe engine or from a remote point, such as acoutrol panel, by means ofhydrostatic pressure applied through a small tube. Alternatively, thelatter expedient may be employed to place the speed under control ofsome factor in a system served by the prime mover, as for example, thepressure in the discharge line of a compressor driven by the primemover, whereby the speed of the prime mover is automatically adjusted tohold the discharge line pressure constant,'etc.

The control system of the invention marks a radical departure fromconventional systems oi prime mover goveming', in that no fly-balls,mechanical linkages or the like, are required for speed-changedetection, but to the contrary, the system is fully hydraulic in itsoperation throughout. speed adjustment and regulation being eflooted bymeans of valve actuating resilient diaphragms or bellows subjected tohydrostatic pressure.

The control system oi the invention has no droop with increasing load,but will maintain the engine speed practically constant, 1. e., withinabout plus or minus 1%, irrespective of load fluctuations.

The response of the system to speed fluctuations from the governingspeed, is at all times in place or in step with the changes in speed andis automatically so adjusted both as to rapidity, intensity and durationof response in relation to the governingspeed selected as also to be inplace or step with the engine acceleration at such speed, wherebyhunting is eliminated at all speeds. In this respect, the inventionconstitutes a radical departure from all known types of governingsystems of which I am aware, in that known types of governing systemsare either inherently incapable of response adjustment for dillerentgoverning speeds, or require tedious response, each time changed.

It is well known that the acceleration of most prime movers is notconstant throughout the speed range thereof, but in general increaseswith speed until the top or no-load speed is approached. If, forexample, the pick-up speed of 2. Diesel engine is plotted against time,starting" from a condition of rest, it will be found that the governingspeed is the speed increases roughly as the square of the time, withconsequent increase in acceleration rate with speed. As a result of thisincreased action of response as the governing speed is increased.Otherwise, the governing action will in general be either too rapid or.too sluggish and either too pronounced or insuillcient to stabilize theengine at the desired governing speed, so that continual hunting willensue.

Existing systems of speed control are inherently incapable of fulfillingthese requirements and hence are productive of serious hunting. Forexample, the response of the simple fly-ball type of governor is fixedand invariable by reason 01' its mechanical construction, so that it isinherently adapted to provide reasonably good regulation only at but oneparticular speed determined by its design. If adjusted, as by means or achange in spring tension or otherwise, to efiect regulation at someother speed, hunting will result for reasons above stated.

The simple fly-ball type of governor is subject to the furtherdisadvantage that it cannot provide close regulation, This results fromthe fact manual adjustments for appropriate changes in 55 that thethrottling action is directly. dependent on the position oi thefly-balls, which in turn is directly dependent on the speed, so that anappre- Various schemes have been proposed for elffecting closerregulation with fly-ball type governors, such for example as by causingslight displacements of the governor to one side or the other of acontrol point, to apply hydrostatic pressure to one side or the other ofa piston actuments, such as bleeder type dash pots, etc., have beenadded for adjusting the governor response in relation to the speed ofregulation, they require careful manual adjustment for each such speed,and hence are objectionable.

In accordance with the fundamentals of construction of the presentinvention, which eliminates such defects, an oil pump, directly drivenby the prime mover and pumping oil through small diameter copper tubing,provides a source of hydrostatic pressure which is variable and whichincreases in direct proportion to the engine speed. This pressure isapplied to a resilient diaphragm carrying preferably the 010- surememberof a needle type speed regulating valve having a separately mountedorifice member cooperating therewith to effect valve closure. A secondpump, driven by the prime mover, is arranged to provide an auxiliarysource of hydrostatic pressure which is substantially constant,irrespective of the engine speed. Pressure from this auxiliary source isapplied under control of the speed regulating valve closure, to adiaphragm actuated differential valve and through it to a similarlyactuated engine throttling valve, whereby closure of the throttlingvalve is under control of the speed regulating valve.

With this arrangement, the speed at which the engine tends to stabilize,will be determined by the initial opening of the speed-regulatingvalve,that is to say, by the initial setting of its closure member in relationto its orifice member. The valve is so arranged, as explainedhereinafter, that the valve closure may be altered independently t theaction of the variable pressure source thereon, whereby the governingspeed or speed of regulation may be adjusted to any desired valuethroughout the full operating range of the engine.

Once the engine has adjusted itself to the governing sped as thusdetermined, further increases or decreases in speed, producedtor-example by load fluctuations, will, by correspondly v rying thehydrostatic pressure applied from the variable source to the speedregulating valve, cause the latter to react in such a way on the enginethrottling valve through the'medium of the auxiliary pressure source andthe, difierential valve, as to restore the engine to its governingspeed.

The system as thus arranged will, however,

have a tendency to hunt, because its rapidity,

acerbic phragm which is separate and distinct from that resilientlysupporting the closure member of this valve. This second diaphragm isarranged to respond to opposed components of the pressure applied to thethrottling valve, a relatively unrestricted component directed to opposechanges in the throttling valve pressure, and an oppositely directedcomponent applied through a restricted orifice of a timing valve. Byappropriately adjusting the opening 01 the timing valve in relation tothe governing speed, displacement of the speed regulating valve orificemember can be so controlled and timed in relation to an initiatingdisplacement of its closure member, as to so adjust the duration andintensity of response of the system in relation to the governing speed,as to eliminate hunting.

The timing valve may be manually adjusted at each governing speed toproduce this result. In accordance with a preferred embodiment of theinvention, however, this adjustment is made automatic by mounting theclosure member of the timing valve on a resilientdiaphragm whichresponds to the source of hydrostatic pressure varying with the enginespeed, the arrangement being such that the opening of the timing valveincreases with the engine speed at just the proper rate to eifect theresult above stated.

In the drawings:

Fig. 1 is a schematic layout of a simplified system inaccordance withthe invention in which the valves are controlled by pressure actuatedresilient diaphragms of-pressure chambers shown in axial section as arealso the valves.

Fig. 2 is a graphical chart showing the manner in which the system ofthe invention varies the fuel supply of a prime mover in response tofluctuations in speed from the governing speed.

Fig. 3 is an embodiment of the invention as employed in practiseandusing pressure actu atedbellows instead of diaphragms for valveaction, the bellowsand valves being shown in axial section and theremainder of 'the system diagrammatically.

Fig. 4 is an axial section 0! a pressure actuated bellows attachable tothe Fig. 3 modification for providing remote or automatic adjustment orthe governing speed.

Fig. 5 is a valve element having a temperature compensated orifice inaccordance with one aspect of the invention.

Fig. 6 is a diagrammatic layout illustrating the invention as applied toan engine driven compressor for automatically adjusting the engine speedto maintain constantpressure' in the compressor discharge line.

Fig. 'i is a graph illustrating the variation with time of the pick-upspeed of a prime mover, such as a Diesel engine. Referring to Fig. 1,apair or positive displacement pumps l, 2, directly or gear driven bythe engine chart 3, pump oil 4 from a sump I through a system of smalldiameter copper pipes or tubes, such as 6 of about $4; inch insidediameter, to a series of pressure chambers 7 to i4, inclusive, each ofwhich is closed at one end by means of a resilient diaphragm, such asIi, a, which is axially displaceable by hydrostaticpressure created inthe chamber. Secured to the diaphragms i5 and Ma respectively, areclosure andoriflce members l6, H of a needle-type speed regulating valvel8, whereby the closure member responds H to movements of diaphragm.ll-while the orifice member responds independently to movements '01diaphragm a. The closure" member ll responds to opposed pressures inchambers 8 and 8, due to its mounting on diaphragm Iia separating thesechambers.

Chambers III, II jointly control the operation of a differential valveI9 containing a. valve stem or closure member 20, conically pointed atits upper end and cooperating with an orifice memher to provide onevalve closure. 22, said closure member 2|! having an enlargedfrusto-conlcal head at its lower end which cooperates with a secondorifice member 23 to provide a second valve closure 24. The closuremember is normally maintained in the position shown by a compressionspring 25. Orifice member 2I is disposed between and rigidly secured tothe diaphragms of chambers I0. and II, so that these diaphragms mustmove in unison, whereby an excess of pressure in chamber ID will forcethe orifice member 2I downward and with it the valve stem 20 against theaction of spring 25 thereby to open the lower valve 24. On the otherhand, an excess of pressur in chamber II will force its diaphragm andwith it the orifice member 2|, upward and away from stem 20 thereby toopen the upper valve 22.

The diaphragm of chamber I2 carries the closure member of a needle-typethrottlin valve 26 disposed in the fuel supply line 21 of the primemover, the arrangement being such that closure of valve 26 increaseswith the pressure in chamber I2. The diaphragm of chamber I3 carries theclosure member of a timing valve 28, the arrangement being such asshown, that the valve opening increases with pressure in chamber I3.

Chambers I and I3 are supplied over pipes 6 and 29 with hydrostatic.pressure from pump I, pressure from which increases, as stated, indirect proportion to the engine speed. This is due to the positivedisplacement type of pump employed, its direct drive by the engineshaft, and its by-pass return 30 to the sump 5 through a valve 3I havinga temperature compensated orifice as described hereinafter. Therefore,as the engine speedincreases, the speed regulating valve II isincreasingly closed and the timing valve 28 is increasingly opened.

The remaining chambers 8 to I2 inclusive, are supplied directly orindirectly with hydrostatic pressure from pump 2. This pump is providedon its outlet side with a by-pass return to the sump containing apressure actuated relief valve 32 closed by-a spring providing constantcompression, for maintaining a constant pressur of about twenty poundsper square inch, in the outlet pipe 33.

This pump supplies hydrostatic pressure pressure is regulated by aby-pass flexible pipe connection 35 extending from chamber I0 to theorifice member I! of-the speed regulating valve I8, through which theoil bleeds out at atmospheric pressure, as indicated at 36, and isreturned to the' sump by means not shown. The pressure in chamber I0,therefore, depends onthe opening of'valve I8.

' Pressure is also supplied from pump 2 to the orifice member 1 23 oflower differential valve closure 24, and through it and overipipe 31 tochamber I2 of the throttling valve, and alsothe lower chamber I I of thedifferential valve, to the v in pressure exerted on its two faces, andsince the latter through the enlarged neck 38 surrounding the valve stem20.

The pressure thus created in the throttlin valve chamber is applied overpipes 39, 40 directly to the upper chamber 8 acting on diaphragm Ilia,and this pressure is also applied indirectly to the lower chamber 9acting thereon, to the latter over pipe 39 and through the restrictedorifice of the timing valve 28 interposed in pipeline 4I. Owing to thisarrangement, diaphragm I-Ga is subjected to opposed components of thethrot- V .valve will, at any given instant, depend on the pressuresinthe three chambers I, I and 9. Chamber I4 is merely a resilient loadingchamber to care for oil displaced from chamber 9 by movement ofdiaphragm Iia.

The operation of this system will be most easily grasped by firstconsidering the control that would be eflected it the diaphragm ISa,timing valve 2i and the appurtenant pressure chambers 8, 9, II and I4were omitted, and the orificelmember II of the speed regulating .valveI8 were rigidly supported. With this assumption, consider the operationas the engine is brought up to the control speed from a condition ofrest.

Prior to starting, the interiors of the various chambers are atsubstantially atmospheric pressure owing to'bleeder and leakage effectsand to the fact that the pumps are not running. The speedregulating andthrottling valves I8, 26 will, therefore, be open to the maximum extent.As the engine gathers speed, the pressure in chamber I will increaseproportionally and correspondingly increases the closure of valve I8.Meantime, pump 2 will have, established a constant pressure in pipe 33,which, operating through bleeder valve 34, will produce a pressure inchamber I0 that increases with increasing closure of valve II due toreduction, in the bypass pressure'escape through pipe 35 and valve I8.As the pressure increases in chamber III,

the deflection of its'diaphragm acting through the orifice member 2|onto stem 20 of the differential valve, will open the lower closure 24thereof against the restraining action of spring 25. Pressure from pump2 will accordingly be simultaneously applied over pipe 22 and throughvalve 24 to the lower chamber 20 of the differential valve and also tochamber I2 of the throttling valve. The throttling valve will thus startto close and reduce the fuel supply, but this action will be arrested ata value approximating that required to maintain the governing speed,owing to the pressure built up in chamber II which, by opposing that inchamber III as regards its action on the chamber diaphragms, permitstheand I2 to secure this result, the excess pressurewill be relieved byatmospheric escape through v valve 22, due to continued upwarddeflection of the diaphragm in chamber II following seating of the valvestem 20.

The governing speed at which the engine will tend to stabilize isdetermined by the initial suddenly tend to speed up further, due forex-- ample to a load fluctuation, each increment of speed will produce acorresponding increment of pressure in chamber 1 to correspondinglyincrease the closure of valve 98. Pressure in chamber In will thusincrease, causing valve 24 to open and increase the pressure in chamberI2, thereby to throttle the engine down, and this will continue untilpressure. in chamber Ii is suflicient to close valve 24.

assists the downward deflection of diaphragm iii to increase the closureof valve l8.

Pressure will accordingly increase in chamber it of the differentialvalve, which will open at its lower closure 24 to apply pressure frompump 2 to chamber l2 controlling the throttling valve 25. The closure ofthe throttling valve will be rapidly increased by this pressure andhence will rapidly reduce the fuel supply in accordance with the portionA-B in the fuel graph of Fig. 2.

Meantime, however, the pressure in chamber i2 is being applied overpipes 39, All to the upper chamber ii acting on diaphragm Mia and overpipes 39, 4i, and through the timing valve 28 to the lower chamber 9acting thereon. Since the pipeline to the upper chamber 8 contains nocon- Should now the engine tend to slow' down unduly, pressure inchamber i will fall and increasethe opening of valve l8. Pressure in itwill, therefore, fall below that required to hold valve 22 closedagainst the opposing pressure in chamber ll, whereupon this valve willopen to reduce the pressure in chambers II and. i2. Reduction ofpressure in II in turn increases the opening of the throttling valve toincrease: the

' fuel supply, thereby to speed up the engine.

The system as described thus far has in gen eral a tendency to hunt forreasons explained at the outset, namely. that the response of thegoverning system is fixed by its mechanical construction and hence doesnot in general conform in speed, intensity and duration of response, tothe rate at which the engine tends to accelerate of rest. The slope ofthis curve gives the ac-- ceieration or deceleration rate at anyparticular speed, such as S1 or 8:. It will be noted that theacceleration rate A1 at speed S1 is much lower than that of A: forspeed-Se. Therefore, a governing system having the proper rapidity,intensity and duration of response to stabilize the engine withouthunting at the speed S2, wound produce m arked hunting if employed at agoverning speed of 81, because its response to speed fluctuations wouldbe too rapid and too pronounced at the lower speed.

In the Fig. 1 system, hunting is automatically eliminated at allgoverning speeds by the resilient mounting of the regulating valveorifice member H on diaphragm Ilia, and by subjection of this diaphragmto opposed components of the striction, pressure in this chamber willbuild up more rapidly than in the lower chamber 9, pressure to whichmust be supplied through the constriction of the timing valve.Accordingly. at the time corresponding to point B, Fig. 2, on the fuelgraph, diaphragm 86a will be deflected downward rather rapidly by theexcess pressure in upper chamber 8, and this will cause the oriflcemember I! of the speed regulating valve to back away to some extent fromthe closure member i6 which is still advancing toward it due to the factthat the engine speed is still increasing as shown in Fig. 2. Thismovement of the orifice member I! in a direction away from the advancingclosure member l5, reduces the rate at which valve l8 continues to closethereafter, and this decreasing rate of closure of valve is is reflectedthrough its action on the" differential valve l9 and throttling valvechamber l2 into'a decreasing rate of closure of the throttling valve 26and throttling valve pressure, the component directly applied throughvchamber 1 and the opposed component indirectly applied through therestricted orifice orthe timing valve 28 and chamher 0.

at time zeroit starts to speed up iii-accordance with the curse portionl-2, due for example to a sudden reduction in load. The increase inspeed will immediately be translated interms of increased pressure inchamber 1 thus increasing hence into a decreasing rate of reduction ofthe fuel supply as shown by the portion BC, Fig. 2,

of the fuel graph.

It will be observed further: in portion B0 of the fuel graph that therate of decrease becomes increasingly smaller until at about point C,the curve becomes horizontal showing that no fur ther fuel reduction isoccurring. This is brought about by two factors. The first is that theincreasing reduction of the fuel supply oflsets increasingly thecontinued tendency of the engine to speed up with the result that itsspeed approaches a maximum at point 2, thus arresting advance of theregulating valve closure member l8 toward the orifice member H. Thesecond factor is that the pressure building up in the lower chamber 9gradually equalizes the pressure on both sides of diaphragm Ilia andthus restores the orifice member. I! to its initial position.

As the engine passes its maximum speed 2,

Fig. 2, and starts to return toward the speed of regulation-inaccordance with the portion 2-! of the speed graph, the actions abovedescribed are reversed. The reduction in speed produces a proportionalpressure reduction in chamber 1 which causes closure member I6 of theregulating valve to back away from orifice member l'l, thus reducing thepressure in chamber ID of the difierential valve. This creates an excessof pressure in chamber H which escapes through closure 22 therebyreducing the pressure in the throttling valve chamber l2, causing thethrottling valve to open rapidly and increase the fuel supply inaccordance with the portion CD of the fuel graph, Fig. 2. I

Meantime, thepressure reduction in chamber i2 is rapidly conveyed. tochamber 8 to produce an upward deflection of the diaphragm due to theexcess pressure thus created in chamber 3.

Orifice member I! thus moves toward the still receding. closure memberll of the speed regu- 1 lating valve, thereby reducing the rate ofincrease of the fuel supply in accordance with portion DE of thefuel-graph. Ordinarily, the engine speed will not be stabilized at thegoverning speed on its first approach, but will oscillate a few times'about the stable speed as shown by portion 3, l

of the speed graph. However, as the engine passes from the maximum speed2 to the minimum speed 3, the movement of the regulating valve stem itaway from the closure member II will be arrested while meantime thepressure in the lower chamber lwill be reduced to that in-l againrestoring the orifice member II to its initial position,-the net effectbeing that at speed 3,

component applied to the diaphragm through the timing valve 28 andchamber 8. It will be noted, moreover, that the unrestricted componentis always in a direction to oppose change in the throttling valvepressure. If, for example,

the throttling valve pressure-is being increased due to increasingclosure of the regulating valve l8, pressurein chamber 8 will alsoincrease and cause orifice member ii to back away from closure member l6tending thereby to prevent furthere increase in the throttling valvepressure, the reverse being true for a decrease in pressure.

The intensity and duration of response of dla-' phragm 16a and with itorifice member II to' changes in the throttling valve pressure, isdetermined by the opening of the timing valve 28. As this valve isincreasingly opened, the intensity and duration of response decreasesdue to the increasing rapidity with which pressure changes in the upperchamber 8 are reflected in the lower chamber 9. Conversely, a decreasein aperture of the timing valve increases the intensity and duration ofcompensation owing to the increasing restriction to pressure changes inchamber 9 provided by the timing valve.

Therefore, by appropriately adjusting the timing valve opening inrelation to the governing l speed, hunting may be eliminated throughoutthe entire speed range of the engine. This adjustment may beaccomplished manually, but preferably it is made automatic as in Fig. 1,by subjecting chamber ii to pressure from pump i which increases withspeed. Accordingly, as the engine speed increases, the timing valve isincreasingly opened automatically to reduce the "intensity and durationof the compensation. By appropriately shaping the closurecharacteristics of the timing valve, as explained hereinafter, the

elusive, respectively. The bellows control the various valves and arepipe connected to the pumps I, 2 and to each other in the same way as inFig. 1, as is shown by the elements similarly designated in each figure.

Each bellows, referring for example to the loading bellows 51, comprisesa thinsheet metal bellows $8 of bronze for example, disposed within arigid metal housing 5! to the base of which one edge SI of the bellowsis secured in a fluid tight seal, the opposite end of the bellows beingsimilarly closed by a floating diaphragm i2. Disposed axially within thebellows is a helical compression spring 63' which maintains the bellowsnormally distended. Hydrostatic pressure may be applied to the interioror exterior of the bellows as desired; to the exterior. as with belelows It, 53, 55, it and I1, and to the interior as with bellows ii, 52and 54,

The compensating bellows ii, 52 are oppositely mounted on a rigidcentral support 64 secured to housing 65, with the free or floatingdiaphragm ends 86, 81 of the bellows rigidly bolted together by means oftie rods 08, 89, so that the diaphragms move as a unit. Diaphragm 68carries the oriflce member ll of the speed regulating valve l8.

Fig. 3 shows a preferred construction of. the timing valve 28. Itcomprises a rod I0 axially displaceable within a sleeve II. The innersurface of the sleeve is provided with a pair of spaced peripheralgrooves 12, 13 and the rod is provided with longitudinal groove 14 ofsufllcient length to'variably overlap the peripheral grooves Ii, 12, asrod I0 is axially displaced within the sleeve.

Axially. drilled bushings 15, I8 threaded intosleeve ll, communicatewith the peripheral grooves 12, .13 therein respectively. Inlet andoutlet sections of'pipe' line ll connect to these bushings respectively,as shown. Rod II is rigidly secured by shaft 11 to diaphragm 18 of.bellows it, the outer surface of which is subjected over pipe 29 tothehydrostatic pressure of pump l which is proportional to the enginespeed. Ac-- for opening the valve at an increasing rate as the rod 10 isupwardly displaced. By properly shaping the groove w shown, the rateatwhich the valve is opening at any particular engine speed can be madeto conform to the acceleration curve of the engine as shown in Fig. 7,whereby hunting will be automatically eliminated at all govclosure ofthis valve will be automatically varied with governing speed, in justthe right proportion to eliminate hunting at all speeds.

Fig. 3 illustrates a preferred practical embodi ment of the invention.The layout and operation of the system are the same as in Fig.1. Theonly important difference is that the diaphragm actuating pressurechambers I to I 3 inclusive of Fig. l are supplanted in Fig. 3 bybellows 50 to '51 inerning speeds throughout the entire operating range.

For manually adjusting the governing speed, a cover plate 80, mounting arotatable wing bolt II, is bolted to the bellows housing 65, with thewing bolt partially threaded into the upper terminal bushing 82 ofbellows 50. Rotation of the wing bolt thus raises or lowers the bellowsto open or close the regulating valve in accordance with the governingSpeed desired. To prevent rotation of the bellows during this operation,a bolt I3 threaded through housing 65, is splined to a vertical rib 84of the bellows housing.

The system may be arranged for remote control or automatic adjustment ofthe governing speed by addition of the bellows 85 shown in Fig.

4. This addition is effected by removing the manual adjusting element ofFig. 3, namely, plate 88 carryirigwingbolt 8|, and substituting thereforthe bellows 85, by threading its stud 86 i into bushing 82 of bellows50, and by bolting its ing speed adjustment is efiected; or thispressure change may be made automatic in accordance with some factor ofthe engine drivensystem to he regnlatedin the manner illustrated in Fig.6 explained hereinafter. r manual adjustment of the governing speed maybe effected at the engine by rotation of knob 89 secured to the upperprojecting end of stud 86.

In Fig. 3, valves 8! and 90 disposed in the pressure line extending frompumps i and 2, are of the temperature compensated orifice constructionshown-in Fig. 5. This valve comprises a cylindrical housing 8| of steelcontaining an orifice member 82 disposed between inlet and outletpassages 83, 88. Axially supported in the housing is a valve stem 850ibronze having a needle point 86 projecting into the orifice of member82. Due to the fact that the bronze stem has a higher coeiilcient. ofexpansion than the steel housing, the stem will expand more than thehousing as the oil heats up and will thus automatically increase thevalve closure to compensate for reduction in viscosity or thinning outof the oil as the. temperature increases and vice versa. Byappropriately shaping the needle point 86 in relation to thetemperature-viscosity characteristics of the oil employed, the valvewill function automatically to oil'er the same: resist-- ance to theflow of oil therethrough'irrespective of temperature.

Again reverting to Fig. 3, oil filters 81, 88 are provided in thepressure lines from the pumps.

. described will be reversed to vary the fuel supply in accordance withportion CD--E of Fig. 2.

52 01' the compensating bellows and over pipe up more rapidly inthelower section, the bellows assembly will at first move downward toback the orifice member I! of the regulating valve away from the stilladvancing stem I6, and will thereafter restore the bellows assembly andorifice member I! to their initial positions. The resultant action onthe fuel supply, will be as shown by portionBC of Fig. 2. As the enginepasses its top speed -2, Fig. 2, the action above Bellows 54 of course,operates'to close valve 24 and to open valve 22 as required formaintaining the proper governing pressure in the throttling valvebellows 55. Pressure on bellows 5% is, during operation, always higherthan that on bellows 53 owing to the smallerpressure area of the former.This permits the use of low operating pressures at the regulating valve58, thereby reducing turbulence and providing smoother op eration. I

Fig. 6 shows diagrammatically at 99 the speed control system of Fig. 3employing the remote control bellows 85 of Fig. 4, for so controllingthe governing speed of a Diesel engine I00 driving a compressor I0'I, asto maintain a constant pressure in the discharge line I02 from thecompressor. The control is effected by applying the pressure of thedischarge line I02 through a In the operation of this system, the escapeof compressed air through nozzle I01 against vane For indicating thegoverning speed in percentage oi the full speed range of the engine, apressure gauge 88 having a scale =range oi zero to one hundred, isconnected to line 8 extending from pump I.

Operation of the Fig. 3 system is essentially the same as that ofFig. 1. The governing speed is adjusted in the manner above described,and this determines the opening of timing valve 28 as explained. at thegoverning speed under a given load, and that the load is suddenlyreduced, the engine will start to speed up thereby increasing thepressure in bellows 58, causing stem I81 of the regulating valve I8 todepress and increase the valve closure. Pressure will accordinglyincrease in the flexible pipe 85 and thus increase the pressure on theprimary bellows 58 of the differential valve I8, causing its diaphragmto depress and open this valve at its lower closure 28' to applypressure from pump 2 to the throttling valve bellows 55 and to thesecondary bellows 58 of the differential valve. The throttling valvewill accordingly start to close to reduce the fuel supply in accordancewith portion AB of Fig. 2. Meantime, the throttlingyalve pressure is ap-Assuming the engine is stabilized plied over pipe 40 directly to thelower section I06, will create a back pressure in line I09 which, actingon bellows 85, will adjust the engine to the speed required to maintainthe desired pressure in the compressor discharge line I02. Assuming theengine to be stabilized at a given speed corresponding to a givenpressure in line I02, if this pressure should increase, the increasedpressure would tend to make tube I 04 unwind slightly, causing vane I06to approach nozzle I01 more closely. The back pressure in line I08 willaccordingly increase to increase the pressure on bellows 85, which,acting through the control system 88 in the manner above explained, willreduce the fuel supply to engine I00, thereby reducing its speed andhence the pressure in discharge line I02 to the control valve. Shouldthe pressure in line I02 subsequently fall, vane I06 will move furtheraway from nozzle I01, thus reducing the back pressure in line I08,thereby causing the engine to speed up until the pressure pressure ofsaidfirst source for correspondingly I varying hydrostatic pressureapplied from said means for causing the other of said members to respondto changes, in pressure applied to said throttling valve from saidauxiliary source for controlling the rate of change in pressure appliedto said throttling valve.

2 An hydraulic speed control for prime movers, comprising: a firstsource of hydrostatic pressure varying as a continuous function of theprime mover speed, an auxiliary source of pressure, a throttling valveresponsive to said auxiliary source, a speed regulating valve havingclosure -and orifice members resiliently supported on pressure actuateddiaphragms, means for causing one of said members to respond toalterations in pressure oi! said first source due to deviation of saidspeed from a selected governing speed for changing in a direction torestore said governing speed the hydrostatic pressure applied from saidauxiliary source to said throttling valve, and means for causing theother of said members to respond to changes in pressure applied to saidthrottling valve from said auxiliary'source for controlling the rate ofchange in pressure applied to said throttling valve.

3. An hydraulic speed control for prime movers, comprising: a firstsource of hydrostatic pressure varying as a continuous function of theprime moved speed, an auxiliary source of pressure, a throttling valveresponsive to said auxiliary source, a speed regulating valve havingclosure and orifice members resiliently supported on pressure actuateddiaphragms, means for ers, comprising:

members to respond to alternations of said pressure due to deviation ofthe prime mover speed from a selected governing speed, Ior changing in Ia direction t restore said governing speed the hydrostatic pressureapplied from an auxiliary source to said differential valve and throughit to said throttling valve, means for causing the other of said membersto respond to changes in said throttling valve pressure for opposingsuch changes, and means responsive to said first pressure source forcausing said opposition to increase with reduction in said governingspeed.

6. An hydraulic speed control for prime mova first source of hydrostaticpressure increasing with the prime mover speed, a speed regulating valvehaving resiliently supported closure and orifice members, means forcausing one of said members to respond to variations or said pressurefor correspondingly vary-- ing hydrostatic pressure applied from anauxiliary source to a pressure actuated throttling valve, and meansincluding a restricted orifice for causing the othenof said members torespond to opposed components of the throttling valve pressure, arelatively unrestricted component directed to oppose changes in thethrottling valve pressure, and an oppositely directed component causingone of said members to respond to alterations of said pressure due todeviation of said speed from a selected governing speed, for changing ina direction to restore said governing speed thehydrostatic pressureapplied from said auxil-v iary source to said throttling valve, meansfor causing the other of said members to respond to changes inpressureapplied to said throttling valve from said auxiliary source forcontrolling the rate of change in pressure applied to said throttlingvalve, and means for adjusting the closure of said regulating valveindependently of said first pressure source for changing said governingspeed.

4. An hydraulic speed control for prime movers, comprising: a firstsource of hydrostatic pressure varying as a continuous function of theprime mover speed, a throttling valve, an auxiliary pressure source, adifierential valve responsive to said auxiliary source for applyingpressure therefrom to said throttling valve, a speed regulating valvehaving resiliently supported closure and orifice members, means forcausing one of said members to respond to alterations of said pressuredue to deviation of said speed from a selected governing speed, forchanging in a direction to restore said governing speed the hydrostaticpressure applied from an auxiliary source to said differential valve andthrough it to said throttling valve, and means for causing the other ofsaid members to respond to changes in pressure applied to saidthrottling valve for reducing therate or change oi said pressure.

5. An hydraulic speed control for prime mov ers, comprising: a firstsource of hydrostatic pressure varying as a continuous function of theengine speed, a throttling valve, an auxiliarypressure source, adifferential valve responsive to said auxiliary source for applyingpressure therefrom to said throttling valve, a speed regulating valvehaving resiliently supported closure and orifice members, means !orcausing one of said applied through said restricted orifice.

7. An hydraulic speed control for prime movers, comprising: a firstsource of hydrostatic pressure increasing with the primelmover speed, athrottling valve, an auxiliary pressure source, a differential valveresponsive to said auxiliary source for applying pressure therefrom tosaid throttling valve, a speed regulating valve having resilientlysupported closure and orifice members, means for causing one of saidmembers to respondto variations in pressure of said first source forcorrespondingly varying hydrostatic pressure applied from said auxiliarysource to said differ- .ential valve and through it'to said throttlingvalve, and means including a restricted orifice for causing the other ofsaid members to respond to opposed components of the throttling valvepressure, a relatively unrestricted component directed to.oppose changesin the throttling valve pressure, and an oppositely directed componentapplied through said restricted orifice.

8. An hydraulic speed control for prime movers, comprising: a firstsource of hydrostatic pressure increasing with the prime mover speed, aspeed regulating valve having resiliently supported closure and orificemembers, means for causing one of said members to respond to variationsof said pressure for correspondingly varying hydrostatic pressureapplied from an auxiliary source to a throttling valve, and meansincluding a timing valve having a restricted orifice for causing theother of said members to respond to opposed components of the throttlingvalve pressure, a relatively unrestricted component directed to opposechanges in the throttling valve pressure, and

an oppositely directed component applied through said restricted orificeof the timing valve, and means for causing said timing valve to respondto said first pressure source for increasing said orifice with enginespeed.

9. An hydraulicspeed control for prime movers,

comprising: a first source of hydrostatic pressure increasing with theprime mover speed, a throttling valve, an auxiliary pressure source, adifferential valve responsive to said auxiliary source i.or applyingpressure therefrom to said throttling valve, a speed regulating valvehaving resiliently supported closure and orifice members, means forcausing one of said members to respond to variations in pressure of saidfirst source for correspondingly varying hydrostatic pressure appliedfrom said auxiliary source to said differential valve and through it tosaid throttling valve, means including a timing valve having arestricted orifice for causing the other of said memhere to respond toopposed 'component of the engine speed.

10. An hydraulic speed control system for prime movers, comprising:first source of hydrostatic pressure increasing with the prime moverspeed, an auxiliary pressure source, a pressure actuated throttlingvalve responsive to said auxiliary sour-cc, a speed remilating valvehaving resiliently supported closure and orifice members, means forcausing one or said members to respond to deviations of said firstsource from a selected pressure corresponding to a selected governingspeed, for altering in a direction to restore said governing speed the.hydrostatic pressure applied from an auxiliarysourceto said throttlingvalve, and means including a timing valve having a restricted orificefor causing the other of said members to respond to opposed componentsof the throttling valve pressure, a relatively unrestricted componentdirected to oppose changes in the throttling valve pressure, and anoppositely directed component applied through said restricted orifice.

11. An hydraulic speed control system for prime movers, comprising: afirst source of hydrostatic pressure increasing with the prime moverspeed, a throttling valve, an auxiliary pressure source, a differentialvalve responsive to said auxiliary source for applying pressuretherefrom to said throttling valve, a speed regulating valve havingresiliently supported closure and orifice members, means for causing onesaid member to respond to deviations of said first source from a.

selected pressure corresponding to a selected governingspeed, foraltering in a direction to restore said governing speed the hydrostaticpressure applied from said auxiliary source to said diilerential valveand through it to said throttling valve, and means including a memberhaving a restricted orifice for causing the other of said members torespond to opposed components of the throttling valve pressure, arelatively unrestricted component directed to oppose changes in thethrottling valve pressure and an oppositely directed component appliedthrough said restricted orifice.

12. An hydraulic speed control system for prime movers, comprising: afirst source of hydrostatic pressure increasing with the prime moverspeed, an auxiliary pressure source, a pressure actuated throttlingvalve responsive to said auxiliary source, a speed regulatingvalve'having resiliently supported closure and orifice members, meansfor causing one of said members to respond to deviations of said firstsource from a selected pressure corresponding to a selected governingspeed, for altering inc direction to restore said governing speed, thehydrostatic pressure applied from said auxiliary source to saidthrottling valve, means including a restricted orifice for causing theother of said members to respond to opposed components of the throttlingvalve pressure, a relatively unrestricted component directed to opposechanges in the throttling valve pressure and an oppositedly directedcomponent applied through said restricted orifice, and-means foradjusting the closure of said speed regulating valve independently ofsaid first source for changi g said governing speed.

13. An hydraulic speed control system for prime movers, comprising: afirst source of hydrostatic pressure increasing with the prime moverspeed, an auxiliary pressure source, a pressure actuated throttlingvalve responsive to said auxiliary source, a speed regulatingvalvehavlng resiliently supported closure and orifice members, means forcausing one of said members to respond to deviations of said firstsource from a preselected pressure corresponding to a selected governingspeed, for altering in a direction to restore said governing speed thehydrostatic pressure applied from said auxiliary source said throttlingvalve, means including a timing valve having a restricted orifice forcausing the other of said members to respond to opposed components ofthe throttling valve pressures relatively unrestricted componentdirected to oppose changes in the throttling valve pressure and anoppositely directed component applied through the restricted orifice ofsaid timing valve, means for causing said timing valve to respond tosaid pressure of said first source for increasing the aperture of saidorifice with increase in speed, and means for adjusting the closure ofsaid regulating valve independently of said first source for changingsaid governing speed.

14. An hydraulic speed control system for prime movers, comprising: afirst source of hydrostatic pressure increasing with the prime moverspeed, an auxiliary pressure source, a pressure-actuated throttlingvalve responsive to said auxiliary source, a speed regulating valvehaving resiliently supported closure and orifice members,

means for causingone of said members to respond to deviations of saidfirst source from a selected pressure corresponding to a selectedgoverning speed for altering in a direction to restore saidgoverning'speed the hydrostatic pressure applied from said auxiliarysource to said throttling valve, means including a timing valve having arestricted orifice for causing the other of said members to respondto-opposed components of 15. An hydraulic speed control system for primemovers, comprising: a first source ofhydrostatic pressure increasingwith the prime mover speed, an auxiliary pressure source, a pressureactuated throttling valve responsive to said,

auxiliary source, a speed regulating valve having resiliently supportedclosure and orifice members, means for causing one of said-members torespond to deviations of said first source from a selected pressurecorresponding to a selected'governing speed, for altering in a directionto re 7 store said regulation speed the hydrostatic pressure appliedfrom said auxiliary source to said throttling valve, means'includinga'timing valve having a restricted orifice for causing the other oi saidmembers to respond to opposed components of the throttling valvepressure, an unrestricted component directed to oppose changes in thethrottling valve pressure and an oppositely directed component appliedthrough the restricted orifice of said timing valve, said timing valveresponding to saidpressure or said first source for increasing theaperture of said orifice with increase of speed, and means responding topressure applied from an external source for ad- Justing the closure ofsaid speed regulating valve independently of said variable source forchangin said governing speed.

16. In a hydraulic speed control system for prime movers: a first sourceof hydrostatic pressure which increases with the prime mover speed,means including a diaphragm-actuated, variable ulating valve forapplying pressure from sai auxiliary source to said throttling valve inac cordance with the pressure on saidregulating valve, said differentialvalve responding differentially to opposed pressure components of saidauxiliary source, a component controlled by said regulating valve, and acomponent applied to said throttling valve.

17. In an hydraulic speed control system for prime movers: a firstsource of hydrostatic pressure which increases with the prime moverspeed, means including a diaphragm-actuated, variable aperture speedregulating valve responsive to and in accordance with said pressure, anauxiliary source of hydrostatic pressure, means includingadiaphragm-actuated, variable aperture throttling valve' responsive tosaid auxiliary source, and means including a difl'erential valve foradiusting the pressure applied to said throttling aperture, speedregulating valve responsive to and in accordance with said pressure, anauxiliary source of pressure, a variable aperture throttling valve, andmeans including a diaphragmactuated diflerential valve responsive tosaid regvalve from said auxiliary source in accordance with the pressureapplied to said regulating valve from said first source, saiddiflerential valve having a pair of valve actuating diaphragms forincreasing and relieving. the pressure respectively on said throttlingvalve.

PAUL A. CONDI'I'.

